In oil-field operations, there is frequently a need to run a well servicing tool from a rig down into a receptacle such as a tubing hanger. In off-shore operations the rig floor is located a substantial distance from the ocean floor where a sub-sea wellhead is located. Tools are run through a string from the rig into the wellhead through a tube assembly such as a riser pipe, or a blow out prevention ("BOP") stack. The down-hole tool is attached to a running string, such as a sucker rod, which is used to run the tool through the center of the stack and place it in connection with the desired receptacle, such as the tubing hanger. It is important that the tool is centered as it is being run through the stack. If not, the tool is likely to impact the internal sides of the stack, causing damage to the stack and the tool itself. Also, if the tool is not properly centered, it may not properly align with the tubing hanger, thereby causing damage to the hanger and the tool.
Solid rigid metal centralizers have been designed for running and retrieving tools. However, these designs rely on the mass of the centralizer for alignment and do not actually protect the down-hole tool as it is being run through the stack. In addition, these nonflexible centralizers often hang up when an obstruction down-hole is encountered. For example, FIG. 1 shows an example of a solid metal centralizer. As shown, the centralizer 10 attaches to the string by threads 102 at one end, and has a down-hole tool 104 attached to an opposite end by threaded bore 106. As shown, down-hole tool 104 is completely exposed, as the centralizer travels downward through the stack. With this type of design some impact between the tool and the sides of the stack may occur, causing damage to the tool 104. These designs do not provide adequate alignment between the tool and the tubing hanger, and thus, further fail to prevent damage from contact between these two members.
Accordingly, there is a need in the art for a device for guiding a down-hole tool which overcomes the above-mentioned problems.